diff --git a/build/Gruntfile.coffee b/build/Gruntfile.coffee
index a34e1fbd4..2340f8823 100644
--- a/build/Gruntfile.coffee
+++ b/build/Gruntfile.coffee
@@ -35,22 +35,8 @@ module.exports = (grunt) ->
 
   # Options
   installDir = grunt.option('install-dir')
-  buildDir = grunt.option('build-dir')
-  buildDir ?= 'out'
-  buildDir = path.resolve(buildDir)
-
-  channel = grunt.option('channel')
-  releasableBranches = ['stable', 'beta']
-  if process.env.APPVEYOR and not process.env.APPVEYOR_PULL_REQUEST_NUMBER
-    channel ?= process.env.APPVEYOR_REPO_BRANCH if process.env.APPVEYOR_REPO_BRANCH in releasableBranches
-
-  if process.env.TRAVIS and not process.env.TRAVIS_PULL_REQUEST
-    channel ?= process.env.TRAVIS_BRANCH if process.env.TRAVIS_BRANCH in releasableBranches
-
-  if process.env.JANKY_BRANCH
-    channel ?= process.env.JANKY_BRANCH if process.env.JANKY_BRANCH in releasableBranches
-
-  channel ?= 'dev'
+  buildDir = path.resolve(grunt.option('build-dir') ? 'out')
+  channel = grunt.option('channel') ? getDefaultReleaseChannel()
 
   metadata = packageJson
   appName = packageJson.productName
@@ -310,3 +296,15 @@ module.exports = (grunt) ->
   unless process.platform is 'linux' or grunt.option('no-install')
     defaultTasks.push 'install'
   grunt.registerTask('default', defaultTasks)
+
+getDefaultReleaseChannel = ->
+  {version} = packageJson
+  if version.match(/dev/) or isBuildingPR()
+    'dev'
+  else if version.match(/beta/)
+    'beta'
+  else
+    'stable'
+
+isBuildingPR = ->
+  process.env.APPVEYOR_PULL_REQUEST_NUMBER? or process.env.TRAVIS_PULL_REQUEST?